1. Field of the Invention
The present invention relates to a read-only information storage medium having one or more recording layers in which the layout of each layer including a lead-in area, a user data area, and a lead-out area are designed to be consistent with other types of information storage media, and a method and apparatus recording/reproducing data on/from the read-only information storage medium.
2. Description of the Related Art
In general, an information storage medium is widely adopted as an information recording medium of an optical pickup system for non-contact type recording/playback. Optical disks, which are an example of information storage media, are classified into compact disks (CDs) and digital versatile disks (DVDs) depending on data recording capacity. Examples of optical disks enabling writing, erasing, and reading of information include 650 MB CD-Recordable (CD-R), CD-Rewritable (CD-RW), 4.7 GB DVD+RW, DVD-Random Access Memory (RAM), and DVD-R/RW. Furthermore, a High Definition-DVD (HD-DVD) with a recording capacity of over 20 GB is currently being developed.
Advances in information storage medium technology continue to result in increases in recording capacity. Representative approaches for increasing recording capacity include using a shorter wavelength light source, increasing a numerical aperture (NA) of an objective lens, and using a plurality of recording layers.
A DVD-ROM having a plurality of recording layers is disclosed in U.S. Pat. No. 5,881,032. FIG. 1A shows a sector address structure of a dual-layer disk disclosed in U.S. Pat. No. 5,881,032. First and second recording layers L1 and L2 on the disk include lead-in areas 1a and 2a, respectively, and lead-out areas 1b and 2b, respectively. A sector address X on the first recording layer L1 increases from an inner circumference Rin to an outer circumference Rout while a sector address X′ on the second recording layer L2 increases from the outer circumference Rout to the inner circumference Rin.
A multi-layer optical disk with two or more recording layers has two different track modes, called opposite track path (OTP) and parallel track path (PTP), which differ in the direction of reading information recorded on the disk. As shown in FIG. 1B, in the OTP mode, the first recording layer L1 is read from the inner circumference Rin to the outer circumference Rout, and then the second recording layer L2 is read from the outer circumference Rout to the inner circumference Rin. In other words, OTP is where a track spiral runs in opposite directions on adjacent recording layers.
FIG. 1C shows an OTP multi-layer optical disk having first through fourth recording layers L1-L4. Here, while the first and third recording layers L1 and L3 contain lead-in areas 1a and 3a and lead-out areas 1b and 3b at the inner and outer circumferences Rin and Rout of the disk, respectively, the second and fourth recording layers L2 and L4 contain lead-out areas 2b and 4b and lead-in areas 2a and 4a at the inner and outer circumferences Rin and Rout of the disk, respectively. Thus, the first and third recording layers L1 and L3 are read from the inner circumference Rin to the outer circumference Rout while the second and fourth recording layers L2 and L4 are read from the outer circumference Rout to the inner circumference Rin.
FIG. 2 shows a PTP dual-layer optical disk. Information is read from the inner circumference Rin to the outer circumference Rout of the first recording layer L1, and then read from the inner circumference Rin to the outer circumference Rout of the second recording layer L2. In other words, in PTP mode, a track spiral on second recording layer L2 runs parallel to that on the first recording layer L1. Thus, the first and second recording layers L1 and L2 contain first and second lead-in areas 1a and 2a at the inner circumference of the disk and first and second lead-out areas 1b and 2b at the outer circumference, respectively.
The first through fourth lead-in areas 1a-4a and lead-out areas 1b-4b contain disk-related information. For a recordable disk, the first through fourth lead in and lead out area 1a through 4b also contain various recording conditions. Thus, the information recorded in the lead-in areas 1a-4a and lead-out areas 1b-4b must be read in order to properly record or read user data.
If the amount of information to be recorded on a multi-layer information storage medium as described above is less than the maximum amount of information that can be written to all of the multiple recording layers, there may be space left on at least one of the multiple recording layers. It is desirable to utilize such an unrecorded portion of a recording layer in a way that is consistent for various information storage media. FIGS. 3A and 3B show recordable single- and dual-layer information storage media where the locations or capacities of lead-in, lead-out, and user data areas are fixed.
As shown in FIG. 4, information is recorded on an entire data area of a first recording layer L1, and then on a portion of a data area of a second recording layer L2. Here, a beam may pass through a recorded portion L1R of the first recording layer L1 and an unrecorded portion L2N of the second recording layer L2, or pass through recorded portions L1R and L2R of both layers L1 and L2. Varying reading conditions for each recording layer irradiated by the beam may adversely affect reading performance.
Thus, there is a need to design the layout of a multi-layer information storage medium to be consistent with other types of media while maintaining optimal reading performance for multiple recording layers. cl SUMMARY OF THE INVENTION
An aspect of the present invention provides an information storage medium in which layouts of a lead-in area, a user data area, and a lead-out area are defined when the amount of user data recorded is less than the medium's full capacity, and a method and apparatus recording/reproducing data on/from the information storage medium.
According to an aspect of the present invention, there is provided a read-only information storage medium having one or more recording layers, each layer containing a lead-in area, a user data area, and a lead-out area, wherein locations of the lead-in and lead-out areas are fixed, and when an amount of user data recorded on the storage medium is less than a full capacity of the storage medium, data other than the user data is recorded on a space remaining on the storage medium after the user data has been recorded.
According to an aspect of the invention, when the storage medium has multiple recording layers, data is sequentially recorded on the layers, and the remaining space is present on a recording layer that the user data is recorded on last.
According to an aspect of the invention, the data other than the user data that is recorded on the remaining space may be dummy data or information on a position where recording of the user data ends.
According to another aspect of the present invention, there is provided a read-only information storage medium having one or more recording layers, each layer containing a lead-in area, a user data area, and a lead-out area, wherein locations of the lead-in and lead-out areas are fixed, and when an amount of user data recorded on the storage medium is less than a full capacity of the storage medium, a space remaining after the user data has been recorded is maintained as a mirror region.
According to another aspect of the present invention, there is provided a read-only information storage medium having a plurality of recording layers, each layer containing a lead-in area, a user data area, and a lead-out area, wherein when an amount of user data recorded on the storage medium is less than a full capacity of the storage medium, the location of the lead-out area of a recording layer that the user data is recorded on last is variable while locations of the other lead-in and lead-out areas are fixed.
According to another aspect of the present invention, there is provided a method of recording/reproducing data on/from a read-only information storage medium having one or more recording layers, each layer containing a lead-in area, a user data area, and a lead-out area, the method includes fixing locations and capacities of the lead-in and lead-out areas and, when an amount of user data recorded on the storage medium is less than a full capacity of the storage medium, recording data other than the user data on a remaining space after the user data has been recorded or maintaining the remaining space as a mirror region.
According to another aspect of the present invention, there is provided an apparatus recording/reproducing data on/from a read-only information storage medium having one or more recording layers, each layer containing a lead-in area, a user data area, and a lead-out area, when the apparatus includes a pickup emitting a beam onto the information storage medium and receiving a beam reflected from the information storage medium, a recording/reproducing signal processor processing the beam reflected from the information storage medium through the pickup to perform signal processing, and a controller controlling the pickup to fix the locations and capacities of the lead-in and lead-out areas and, when an amount of user data recorded on the storage medium is less than a full capacity of the storage medium, to record data other than the user data on a remaining space after the user data has been recorded or maintain the remaining space as a mirror region.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.